and when it was purchased by the university of oklahoma in 1985 it contained about 25,000 commercials, and it's grown today to over 95,000. >> you had mentioned negative campaigning. when did that become more precedent in these commercials? >> that has actually been the case in almost every campaign. some of the earliest material we have is negative campaigning. we've got ads from adlai stevenson against eisenhower. we have the famous daisy girl ad that was against goldwater. it's very easy in the visual medium of a short television ad to connect things with powerful imagery. >> ten, nine, eight, seven, six, five, four, three, two, one, zero.